Cement for lightweight concrete and method of making



[UU'ZSU UNIT-ED Patented Sept. 5, 1950 M J STATES PATENT OFFICE a ar CEMENT FOR LIGHTWEIGHT CONCRETE AND METHOD OF MAKING Norman C. Ludwig, Chicago, 111., assignor to Universal Atlas Cement Company, a corporation of Indiana No Drawing. Application March 17, 1948, a Serial No. 15,497 y Claims. (Cl. 106-86) This invention relates generally to hydraulic cement and, in particular, to a cement suitable for making porous or l i ghtwe igl it concrete, by reason of its remarkable air-entrainifig iiioperty.

This is in part a. continuation of my application Serial No. 668,321, filed May 8, 1946, now abandoned, for "Cement Composition and Method of Making.

Light-weight concrete, 1. e., concrete having a density less than about 140# p. c. f. (pounds per cubic foot), the density of ordinary concrete, is desirable for many purposes, such a l ls, W. Such concrete has been ma e ere fore principally by utilizing lightweight aggregates, such as Haydite iexpanded clay) or vermiculiteiexfoliated mica),'c6ntafri'- ingbntrapped air which gives them a low density. It has also been proposed to incorporate in concrete mixes air-entraining or ioam promade therefrom. The s bility of the foam produced, however, is somewha "an""c'o' fild be desired, resulting in shrinkage of the concrete after placing. I have further discovered 5 that the addition of wl 1 eat flour to Portland air-entraining property characteristics of a given addition of Vinsol resin, but the foam produced is very stable. I have also discovered that the addition of from 1% to 2% wheat flour to a cement mix containing from 0.0625% to 0.40% (of Vinsol resin renders the abundant foam produced by the latter exceptionally stable so that castings thereof exhibit very little shrinkage on setting.

The stabilizing effect of the wheat-flour addition is not apparent when used with air-entrain ducingagents not only for the production of mg agents other than Vinsol resin so I conclude Tight-weight concrete but also to increase the plasticity and workability of the wet mix andthe resistance of the concrete to weathering. Cement mortars have been thus produced containing entrained air up to about 20% by volume. Concrete made from so-called air-entraining cements known heretofore, however, usually contains only from 2 to 5% air by volume. Such small amounts of entrained air do not reduce the weight of concrete to the extent necessary for most uses of light-weight material, where 50 to 60% air is sometimes wanted. Attempts to entrain such large quantities of air by adding air-entraining agents to cement have not heretofore been successful because the foam produced lacks stability and proper size distribution. It is the object of my invention to provide a cement adapted for the manufacture of lightthat there is a reaction of some kind between the resin and flour. The combination of Vin-,

dry cement powder and mixed thoroughly therewith before the addition of ater. The eifectiveness of wheat flour as an air-en raining agent in itself is improved, however, by dissolving it in an alkaline solution. The air-entraining efiect of t e w ea our further increased if the flour is milled from a high-gluten wheat. Instead of wheat flour, the g u en erive erefrom may be employed. Soy-Bean flog; may be used inweight concrete, having an air-entrainin a ent stead of Wheel}; Vi'nSOl resin s Pr incorporated therein which is mgfily Elfectivem 40 erably added m the form of .2 Elonmdflute producing foam or bubbles having a highstability, and is 0 cap, re y obtainable, and usable without material modification of conventional practice in mixing, pouring and curing.

sodiu h droxide.

Table I below shows the air-entraining effect of additions of various amounts of wheat flour alone or equivalent (gluten, soy-bean flour) to LAHIVHNLI I have i e d that th addition t rt.- Portland cement. The samples from which the n of from 0.0625% to 0.4% by weigh data given were obtained were made by mixing of the frac ion of a coal-tar h drocarbon ex;- slurries of parts of water to parts of Porteum fa 11d high-earl -streng'th'"cement plus the spec? fled additive in the amou'n't"'- stated. After mix- 3 was measured and the air content calculated from the density of a similar slurry consisting of water and cement only.

Table I Compressizve siggngfttg, p. s. on a r Dry Additive Parts f f fi 3 amper 100 Parts (Jement p I cent at 70 F. at 140 F.

None 109 2, 409 4, 850 Ordinary Wheat Flour:

6... 70 35. 8 375 Not Set 62 43. 1 Not Set Not Set v Hilgh Qluten Wheat lour:

51 53.2 169 Not Set 62 43.1 Not Set Not Set 57 47. 7 242 Not Set 62 43.1 Not Set Not Set 69 36. 7 Not Set 936 67 38. 6 Not Set 941 Table II Compressive Strength, Paste p. s. 1., 2" cube after Additive, Parts per Density 3 daysl00 Parts Cement c. f Cent at 70 F. at 140 F.

1 Ordinary Wheat Flour 77 29. 4 l, 113 l, 683 1 High-Gluten Wheat Flo 49 55. 0 414 478 l Gluten 63 51.3 306 352 These results show that w is much more effective in impar ing a r-entraining properties when dded as a solution than when added dry to the cement'powwfnstead of ad g aline solution of wheat flour or gluten to the cement, I may add it to the cement w from the kiln an rind the solution an I may also add the powdered inso resin he neutralized Vinsol resin so n tion *3 the dry cemen or e cemen 0 er me grinding process.

Light-weight concrete may be readily made using one of the air-entraining additives disclosed above and a li ht a regate such as Haydite or vermiculite. e 0 owing table gimms of tests using wheat flour with these aggregates and also the characteristics of concrete made with these aggregates and without any additive, for the purpose of comparison. The cement-aggregate ratio used in all cases was 1:4.

1 After 7 days in moist cabinet and 7 days in air.

Of the aggregatesreferred to in Table III, that identified as Haydite is an expanded clay obtained by processing ordinary clayiat tempemtures of approx mately"f2m ilifffi'xparislofiis 'fifcmcausedby are 'effectsfi'f'xpanding gases on the components in a semi-fluid state. The composition of the clays used in producing Haydite varies, depending on their source. The apparent density of Haydite is from about 60 to 70 p. c. f., depending upon the raw materials, degree of'expansion, and gradation of the product.

The jyern iculitf referred to in Table III is an expanded f ica manufactured by treating mica'jqie at high temperatures. The process" is sanewnatsimuar to poppingcorn as the mica ore is moved across the surface of a hot plate.

In. the mica ore, small amounts of water are held between each lamination, and when suddenly exposed to high temperatures, the water changes to steam and explodes the particles into cellular granules about fifteen times the original size. The apparent density of the "Vermiculite varies from about two to twelve pounds per cubic foot, depending upon the ore used, the treatment and 4 the gradation.

Additives capable of entraining sufficiently large amounts of air, i. e., above approximately would make possible the production of light-weight concrete without requiring the use 5 of aggregates, such as Haydite and vermiculite. which lighten concrete in which they are used by the air entrapped therein, or with the use of smaller amounts thereof. Where it is desired to entrain such large amounts of air in a wet 5 cement mix, however, the wheat flour, gluten or soy-bean flour when added alone is not as effective as desired and larger amounts are required. These amounts affect the hardening properties of the cement as shown by the results given in Table I. I have discovered that the fraction of the extract of pine wood in a coal-tar hydrocarbon 'i's'y'r y effect'ive when addedtfi Portland cement, in imparting air-entraining properties (30 to the mix. This material is known as Vinsol/ resin. When neutralized with NaOH to form a rosin sba and added to cement, it produces an abundant foam in the mix. The foam while plentiful is not as durable as desired and I ac- 5 cordingly prefer to use wheat flour or its equivalent as an additive to supplement and cooperate with the Vinsol resin. The flour not only acts as d an air-entraining agent itselfbiit (which is more important)lefids reiiiarkable stability to the foam produced by the Vinsol resin. The coin- Bin'deffect of the two additives is superior to that of ither one, considering the desirability of a minimum amount of additive and minimum shrinkage, i. e., foam stability, as well as maxi- 76 mum air content. The following table gives the 5 results of tests using Vinsol resin and wheat flour alone and then both together:

fords a practical solution for the problem of entraining large quantities of air into a wet cement Table IV Easies Density All Bhlillk- Additive-Per Oent Mix, Content, age, Pe cubes p. c. f. Per Cent Cent N VR0.0825 78. 5 27. 8 4. 7 32 $2 NVR0.125--- 51. 7 52. 5 6. 5 147 L3. 1 60. 3 6. 9 107 188 B2. 9 23. 4 2. 4w 1, 027 72. 5 33. 0 2. 6 268 652 77. 0 29. 4 2. 1 399 1, 113 62. 8 41. 9 2. 5 169 377 74. 8 31. 0 2. 5 I 473 58. 0 46. 4 2 7 180 358 51. 3 52. 6 2. 8 125 253 45. 0 68. 4 2. 9 85 195 65. 0 40. 0 2. 4 215 522 w. 1 45. 2 2 5 m 825 4B. 7 55. 0 2. 9 111 222 42. 2 61. l 3. 1 105 187 1 Average of three spec imens. iSqOIUtiOll consists of 5% wheat flour dissolved in 1.5% solution of NaOH VR-Ne ized V N aOH solu on i resin solution. 23 g. resin dissolved in 100 ml. ot a 3.5%

4 SW-Wheat Flour solution. 5 g. wheat flour dissolved in 100 ml. of a 1.5% NaOH solution.

I W-Wheat Flour used as powder with cement.

mix and maintaining the resulting foam substantially stable over the setting period so that shrinkage during setting is not serious. It also makes possible the production of lightweight concrete with aggregate other than lightweight aggregates, using a minimum amount of the latter or none at all. Iclaim:

1. In a method of making porous concrete,

Table V 0312 1 water Per t Density, lb./cu. it. a. in No. Additive, Per Cent Weight Aggregate. Parts by Weight Per Cent A cubes Test oi Cement oi Cement Weight content Omt. w t D 9 7 Concrete Concrete 3 De. 7 Da.

1 Nnnn Non 0 10B. 7 107. 2 2100 2-- 0.4 NVR +2 W N 62 41. 3 33. 2 155 0.4 NVR+1 W- N 48. 7 40. 9 111 222 52. 6 51. 3 4B. 5 125 253 78. 0 39. 0 277 39. 5 24. 4 47 43. 2 25. 7 113 38. 0 28. 0 212 43.3 25. 8 69 g. wheat flour dissolved in 100 ml. 01 a 1.5% NaOH solution.

ca 0 r I 10 5 I The air content cannot be determined with any degree of accuracy in concrete mixes containing aggregates such as asbestos fiber, vermiculite and cellulose iiber.

The results obtained in Tests 2, 3, and 4, as compared to those of Test 1. show that lightweight products can be easily produced by the use of the combined additives without the addition of a lightweight aggregate. The results of Tests 5 and 6 illustrate the decrease in the density of the concrete product obtainable by the use of the combined additives and show the saving that can be made in the quantity of asbestos fiber by replacing that aggregate with entrained air. Tests '7, 8 and 9 are included to show that the combined additives will work equally well with three other common lightweight aggregates.

It will be apparent from the foregoing that my invention provides a highly efiective i'oamproducing additive for Portland cement which is I cheap, readily available and easy to use. It a!- the steps including adding to Portland cement from 1 to 2% wheat flour by weight and from 30 .0625% to .40% by weight of the neutralized fraction of the coal-tar-hydrocarbon extract of pine wood which is insoluble in petroleum hydrocarbons, and adding water to produce a wet mix.

2. The method defined by claim 1 characterized by said wheat flour being dissolved in an alkaline solution.

3. The method defined by claim 1 character- 70 ized by said fraction being dissolved in an alkaline solution.

4. As a new composition of matter, a mixture of Portland cement, from 1 to 2% wheat flour by weight and from .0625% to .40% by weight of the neutralized fraction of the coal-ter-hydro- Portland cement from 1 to 2% of wheat flour by 5 weight; and from .0625% to .40% by weight of the neutralized fraction of the coal-tar-hydrocarbon extract of pine wood which is insoluble in petroleum hydrocarbons.

NORMAN C. LU'DWIG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 254,247 Fronc Feb. 28, 1882 2,207,339 Camp July 9, 1940 2,215,812 Kaplan Sept, 24, 1940 10 2,228,019 Scripture Jan. 7, 1941 

1. IN A METHOD OF MAKING POROUS CONCRETE, THE STEPS INCLUDING ADDING TO PORTLAND CEMENT FROM 1 TO 2% WHEAT FLOUR BY WEIGHT AND FROM .0625% TO .40% BY WEIGHT OF THE NEUTRALIZED FRACTION OF THE COAL-TAR-HYDROCARBON EXTRACT OF PINE WOOD WHICH IS INSOLUBLE IN PETROLEUM HYDROCARBONS AND ADDING WATER TO PRODUCE A WET MIX. 